PB2105: REAL WORLD EXPERIENCE WITH POLATUZUMAB IN COMBINATION WITH BENDAMUSTINE AND RITUXIMAB FOR R/R DLBCL IN 3 ACADEMIC CENTERS IN MADRID, SPAIN.
Authors: M. Corrochano, S. Nistal, V. Pradillo, A. Alonso, C. Alaez, M. Tercero-Mora, I. Delgado, J. M. Sanchez, E. Marti, A. Segado, G. Benzo, A. Escudero, J. M. Fernández-Rañada, C. Martinez Chamorro
Journal: HemaSphere (2022)

Background: On 2019, the FDA and later the EMA granted approval to polatuzumab vedotin-piiq, a CD79b-directed antibody-drug conjugate indicated in combination with bendamustine and rituximab (P-BR) for adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), not otherwise specified (NOS), after at least two prior therapies. P- BR has demonstrated (NCT02257567) better overall response rates (complete and partial responses) compared with BR alone (63% vs 25%) and response durations of at least 12 months in 48% of the patients. The most common adverse reactions with P-BR (incidence at least 20%) included cytopenias (most common reason for treatment discontinuation), peripheral neuropathy, fatigue, diarrhea, pyrexia, decreased appetite and pneumonia. Serious adverse reactions occurred in 64%, most often from infection. Aims: To analyze results in terms of efficacy and safety of the P-BR regimen in real life conditions. Methods: Observational, retrospective study in 3 academic centers. Adult patients (≥ 18 years old) diagnosed with DLBCL NOS R/R who received P-BR between July 2019 and December 2021 were included in the analysis. Results: 11 patients were treated with P-BR. The mean (SD) age was 70.1 (8.2) years (Range 57-81 years). Cell of origin was informed in 9/11 cases, 6 of them were activated B-cell (ABC) subtype. No double-/triple-hit lymphomas were confirmed. The median number of prior lines of therapy before P-BR was 2, with most patients (63%) refractory to the last treatment. All patients had received anti-CD20 (Rituximab) on prior treatments and only 2 (18%) Bendamustine. Baseline characteristics are shown in Table 1. Efficacy Seven patients were evaluated by PET-CT after 3 cycles, 4 (57%) achieved CR and 3 PR (43%). Five patients achieved CR by PET-CT at the end of treatment. One of these patients is still in CR after 12 months of follow up and three of them after 24 months from the start of P-BR. One patient relapsed after 19 months. Of the patients achieving CR, all of them had responses >12 months. Only 3/5 completed the 6 cycles scheme, 1 patient received 5 cycles (treatment was interrupted due to an invasive fungal infection) and 1 patient received only 2 cycles as bridge therapy for and autoHCT and achieved CR after transplantation. 1 patient was refractory to treatment and progressed after 2 cycles. Toxicity: All patients were evaluated for toxicity. 63% (7/11) of them presented hematological toxicity, mainly neutropenia which required GCSF administration and 71% RBC transfusion. Two patients required hospital admission because of neutropenic fever. There were 3 documented cases of SARS-CoV-2 infection. Two patients had moderate disease with bilateral pneumonia (vaccinated) after the 2º cycle of treatment which is temporarily interrupted. One patient completed 6 cycles but died of severe SARS-CoV2 infection (unvaccinated) before being assessed for response at end of treatment. Two patients interrupted treatment definitely because of toxicity: severe cytopenia and invasive fungal infection. No other extra hematological toxicities were reported. Image:Summary/Conclusion: The P-BR regimen provides sustained good results for patients with R/R DLBCL who have failed treatment with prior therapies. Cytopenias were the most frequent form of toxicity and were easily addressed in most cases. In our experience, SARS-CoV2 infection has been a challenge due to delay in treatment and high morbidity and mortality.